This application is based on and claims priority under 35 U.S.C. xc2xa7119 with respect to Japanese Application 2000-158624 filed on May 29, 2000, the entire content of which is incorporated herein by reference.
This invention generally relates to an openable and closable vehicle door. More particularly, the present invention pertains to a sliding vehicle door provided with a driving mechanism and an electric motor for slidably moving the door between one position in which an opening in the vehicle body is uncovered (i.e., exposed) and another position in which the opening in the vehicle body is covered.
A known vehicle sliding door for exposing and covering a door opening portion provided in a vehicle body is described in a Japanese Patent Application Publication published as Toku-Kai-Hei 10 (1998)-18708. This vehicle sliding door is slidably supported by a center guide rail which extends in the front and rear directions on the vehicle body. The opening and closing device is installed in the vehicle body and is provided with a driving mechanism and an endless cable (i.e., a closed loop cable). The driving mechanism serves as a driving source and includes an electric motor and an output drum. The cable, which is operatively connected to the sliding door, is retracted by the output drum of the driving mechanism. Further, the cable is guided by the center guide rail from an end of the guide rail at the vehicle rear side and is folded back by a guiding pulley arranged at the other end of the center guide rail at the vehicle front side.
During operation, the cable is retracted by the output drum or is released from the output drum in correspondence with the rotation of the output drum produced by the driving operation of the motor. The cable is thus reciprocated in both directions along the center guide rail to move the sliding door for covering and uncovering the door opening portion through reciprocating movement of the cable.
The aforementioned vehicle sliding door opening and closing device may suffer from several disadvantages and drawbacks. The driving mechanism is disposed in the vehicle body and so the vehicle body must have an exclusively used mechanism to maintain an installing space for the driving mechanism, to define an opening portion for disposing the cable. Accordingly, difficulties may arise with respect to installation of the known opening and closing device which is accommodated in the vehicle body. Additionally, because the guiding pulley is disposed at the other end of the center guide rail, the center guide rail has to be long enough to accommodate the guiding pulley. Therefore, the driving mechanism installed in the vehicle body may project in the direction of the interior and thus may limit the size of the vehicle compartment. Furthermore, as the cable is reciprocated in opposite directions along the center guide rail, manual sliding operation of the sliding door may require a relatively significant amount of power to overcome the sliding resistance of the cable when the driving mechanism is inactive.
A need thus exists for an improved vehicle sliding door opening and closing device which has sufficient space for installing the driving mechanism without the same restrictions as the known device.
It would also be desirable to provide a vehicle sliding door opening and closing device that does not adversely impact the volume of the vehicle interior to the same extent as the known device.
Further, a need exists for a vehicle sliding door opening and closing device that is able to control increases in the sliding resistance caused by the cable.
According to one aspect of the invention, an opening and closing device for a sliding vehicle door that covers and uncovers a door opening portion defined in a vehicle body includes a driving mechanism installed in the sliding vehicle door and provided with an output drum and a cable wound by the output drum. The cable includes two ends that are operatively engaged with the vehicle body.
According to the present invention, the driving mechanism is installed in the sliding door and so less difficulty arises with respect to installing the driving mechanism. Further, the opening and closing device of the present invention is able to provide sufficient accommodation space for the driving mechanism.
Additionally, the cable is not required to be reciprocated relative to the guide rail so that a guiding pulley is not required with the guide rail. Therefore, the length of the guide rail is not required to accommodate the guiding pulley. Further, the opening and closing device of the present invention does not increase the sliding resistance caused by the cable.
According to another aspect of the invention, an opening and closing device that moves a sliding vehicle door mounted on a vehicle body between a closed position in which a door opening portion defined in the vehicle body is covered and an open position in which the door opening portion is uncovered includes a motor mounted on the sliding vehicle door, an output drum operatively connected to the motor to rotate in response to operation of the motor, a cable wound about the output drum and having at least first and second ends, and a pair of spaced apart guide pulleys mounted on the sliding vehicle door. One portion of the cable extending from the output drum to the first end of the cable engages both of the guide pulleys, while another portion of the cable extending from the output drum to the second end of the cable engages both of the guide pulleys. The first end of the cable is operatively engaged with the vehicle body and the second end of the cable is operatively engaged with the vehicle body.
According to a further aspect of the invention, an opening and closing device that moves a sliding vehicle door mounted on a vehicle body between a closed position in which a door opening portion defined in the vehicle body is covered and an open position in which the door opening portion is uncovered includes a motor mounted on the sliding vehicle door, an output drum operatively connected to the motor to rotate in response to operation of the motor, a cable wound about the output drum and having at least first and second ends, a guide rail mounted on the vehicle body, and a guide roller mounted on the sliding vehicle door and positioned in the guide rail for movement along the guide rail during movement of the sliding vehicle door between the closed and open positions. The first end of the cable is connected to either the guide rail or the vehicle body, and the second end of the cable is connected to either the guide rail or the vehicle body.